The invention relates to an apparatus for actuating a switch shaft which is operatively connected with a switchable bottom bracket bearing gear for a bicycle or the like and is held in a hollow-cylindrical drive shaft, which switch shaft is jointly displaceable relative to the drive shaft in the axial direction with the first coupling member which is arranged at the one end of the drive shaft rotatable about its longitudinal axis and is to be connected in a form-locked manner with the power-transmitting functional elements of the bottom bracket bearing gear.
Switchable bottom bracket bearing gears for a bicycle or the like are known from specifications (EP-A 0 562 470 and EP-A 0 666 212) in which a coupling member operatively connected with a switch shaft as well as a drive shaft can be brought into engagement with a chain wheel or with a sun wheel arranged at a distance therefrom or vice-versa for the purpose of achieving a change in the rotational speed, with the movement of the switch shaft oriented in the axial direction for the switching operation being effected by means of a switching member which is arranged on the outside of the crank and can be actuated with the foot. The individual switching member can be arranged either in the form of a thrust member arranged in a recess of the crank and in the shape of a button, or in the form of a longitudinal thrust member which is held on the outer side of the crank and is deflectable relative thereto.